Note: Descriptions are shown in the official language in which they were submitted.
~Z~35356
P~PPET-VALVE-CONTROLLED
FLUID NOZZLE APPLICATOR
The present invention relates to fluid nozzle appl;-
cator systems, being more particularly directed to such sys-
tems controlled by mechanical or electromechanical valvin~
devices for enabling metered intermittent, patterned, or
continuous coatings to be deposited in controlled thickness
from the nozzles upon moving webs or other surfaces, as in
the application of hot melt adhesives and other coating
fluids such as those described, for example, in United
States Patents Nos. 3,595~204, 4,020,194 and 4,476,165.
Prior valves for enabling such operation, particularly
with longitudinal slot nozzles and the like, as described in
said patents, have included two-way poppet valves with a
single fluid supply inlet to the valve assembly (such as the
type described in "Extruder Valve", a 1977 bulletin of Acu-
met-er Laboratories, Inc., the assignee of the present inven-
tion), and more recently three-way poppet valve structures
enabling precise and constant thickness patterns oE f.luid
coating with negligible after-drool and with a very short
stroke that permits more rapid on/off cycLe times--such
being described in my United States Patent No. 4,5hS,217.
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~ hile such and other valving structures are particu-
larly suieed to the types of fluid extrusion or deposition
nozzles above-referenced and similar extruders, there are
occasions where it is desired to spray or even atomize or
fiberize the fluid upon the moving web or other surface,
which requires the use of finer nozzle orifices and even
needle-like nozzles with fine dispensing openings. It is
mo}e particularly to the adaption of poppet-valve structures
and preferably said three-way poppet valves to such extruding
spray-like or atomizing or fiberizing nozzles or heads that
the present invention is principally (though not exclusively)
directed, such nozzle dispensers having properties and
characteristics often quite distinct from the before-men-
tioned types of extrusion nozzles.
An object of the present invention, accordlngly, is to
provlde a new and improved poppet-valve-controlled fluid
nozzle applicator particularly useful, though not exclusi-
vely, with such extruded sprav or atomizing type disoells~ng
applicators and the like.
A further object is to provide such a novel applicator
that operates with a preferred three-way poppet valve.
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Still another object is to provide a novel
applicator for the intermittent (and continuous)
extrusion or spray of fluids through fine needle-like
nozzles or dispensers; and further, where desired, to
enable the shaping, varying or controlling of the fluid
spray in a defined manner during the extrusion.
Other and further objects will be explained
hereinafter and are more particularly delineated in the
appended claims. In summary, therefore, the present
invention may be considered as providing a poppet
valve-controlled fluid nozzle applicator system having,
in combination, a longitudinally extending,
reciprocally mounted valve stem carrying a poppet valve
constrained within a fluid supply chamber communicating
with a pressurized and metered fluid supply source, the
poppet valve having a downwardly converging surface
terminating in a valve tip; a nozzle mounted to depend
from a region of lowermost reciprocation of the valve
tip, the nozz:Le having a first passage therein with an
opening at an upper end thereof into which the valve
tip may fit to block fluid flow from the chamber into
the passage when the valve stem reciprocates to a
lowermQst position, the valve tip engaging a portion of
the nozzle surrounding the opening along a line-contact
circle the diameter of which has a magnitude that is a
minor portion of the magnitude of the diameter of the
poppet valve, the nozzle having a second passage
therein that is substantially narrower than the first
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passage, the second passage having an upper end that
communicates directly with the lower end of the first
passage and having a lower end with a fine bottom
orifice thro~lgh which fluid exits upon elevation of the
valve tip from the region of lowermost reciprocation; a
dispensing head disposed about the nozzle and having a
bottom aperture in substantial alignment with the
bottom orifice of the nozzle, the dispensing head
having means for adjusting the position of the
dispensing head relative to the nozzle within a range
of positions from a position at which the bottom
orifice of the nozzle is just above the bottom aperture
of the dispensing head, through a position at which the
orifice and the aperture are substantially flush with
one another, to a position at which the orifice is
below the aperture, the nozzle having a conical outer
surface with an apex region adjacent to the bottom
orifice and the dispensing head having a conical inner
surface surrounding and spaced from the conical outer
surface of the nozzle and having an apex region
adjacent to the bottom aperture; and means for
directing air conically convergingly inward in the
space between the conical surfaces and thereafter upon
fluid exiting from the orifice as the fluid is in free
flight therefrom, and in which the nozzle has a
cylindrical portion terminating the apex region thereof
whereby the conically convergingly inward directed air
is redirected along the direction of fluid exiting from
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the bottom orifice, the diameter of the aperture being
greater than the diameter of the cylindrical portion so
that the aperture remains open even when said
cylindrical portion is within said aperture.
The invention will now be described with
reference to the accompanying drawings, Fig. 1 of which
is a longitudinal section of the apparatus of the
invention in preferred form;
Fig. 2 is an isometric view thereof; and
Figs. 3A, 3B and 3C are fragmentary
longitudinal sections of different positions of
adjustment of the nozzle portion of the apparatus of
Figs. 1 and 2;
Fig. 5 is a view similar to Fig. 1 of a
two-way poppet valve embodying features of the
invention:
Figs. 4 and 6 are respectively system block
diagrams showing how the valve-nozzles of Figs. 1 and 5
may be operated for the purposes herein; and
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Figs. 7A and 7B illustrate metering pump mounting ad-
jacent the respective three-way and two-way poppet valve
nozzle applicator structures of Figs. 1 and 5 (Figs. 4 and
6).
Referring to the drawings, for illustrative purposes,
as before stated, the inventlon is first described in connec-
tion with a preferred three way poppet valve of the type dis-
clo.sed in said Patent No. 4,565,217, having a housing or body
1 provided with longitudinally extending valve stem or piston
3 axially reciprocally mounted within communicable upper and
lower (as shown) longitudinally displaced fluid chambers 5
and 5'. The lower chamber 5' transversely communicates with
a fluid supply source at 7', such as a pressurized metered
hot melt or other coating fluid or adhesive fluid supply, as
described in said patents, for example, and the upper chamber
5, with a fluid return path 7. The valve piston or stem 3
carrie.s at its lower end, ln the orientat:Lon shown, a valve
head 9 having upwardly and downwardly conical converging sec-
tions 9' and 9" contained within the lower chamber 5'. The
upper converging conical section 9', when the stem 3 is reci-
procated to its upperntost position, bears agains~ the lower
end region 11' of the valve seat opening 11 communcating the
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lower and upper chambers 5' and 5 to close off such communi-
cation. The lower oppositely or downwardly converging coni-
cal section 9 of the poppet valve head 9 terminates in a
conical tip T that, when the valve stem reciprocates down-
wardly to its lowest position or point, enters and blocks off
the top of a narrow hollow insert or other recess 13 in the
upper portion of a conically terminated extrusion sprav or
dispensing nozzle 15. The lnsert or recess 13 communicates
dlrectly with a hollow needle-llke thinner tube or stem N
(that may actually be a hyperdermic- like hollow needle or
other tube including a tubular recess preformed in the nozzle
cone) ln the lower portlon of the nozzle houslng 15 that,
when the valve stem tlp T ls elevated to open fluid communi-
cation from the lower chamber 5' into the nozzle hollow
insert 13, exits fluld through the lower aperture(s) N' of
the needle nozzle tube or stem.
Preferably, as shown ln Figs. 1 and 2, an atolllizer head
coaxlally surrounds the conical nozzle houslng 15, but with a
V-shaped somewhat conlcal space V provlded therebetween for
enabling relatlve longltudinal adjustment of the position of
the nozzle housing 15 and the aperture A' of the head A and
for later-described conical air flow when desired. Such ad-
~ustment, as by the threaded section 15', Fig. 2 (or other
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adjustable structure including slidable adjustment), ~
control the fluid exiting point of the needle, tube or stem
opening(s) N' to recessed positions above the aperture A' of
sonewhat larger diameter (Fig. 3A), or to substantial align-
ment or a flush position therewith (Fig. 3B), or to extended
positions beyond (Fig. 3C), thereby to varying the character
of the fluid extrusion for adjustable effects. The recessed
position of Fig. 3A has been found to cause the extruded
spray to assume a mainly continuous filament or fiber charac-
ter as air introduced at 20 and conically intersecting the
extruded fluid in free flight outside and below the nozzle
opening N', bonds or stretches the fluid into a continuous
filament form; the flush position of Fig. 3B, producing a
combination of fiber or filaments and droplets; and the
extended position o~ Fig. 3C, producing a spray mainly of
droplets. This adjustment thus has been found to permit con-
trol of the nature of the extruded spray or depositlon and
the ratio of fibers-to-droplets, for exampLe.
The valve stem 3 is mechanically reciprocated in the
illustrative embodiment of Figs~ 1 and 2 by pneumatic
pressurized-fluid means acting first downwardly upon the air
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piston head 3' of the valve stem or piston 3 from air inlet
(outlet) 2 in an air manifold body 4 at the top of the valve
body 1, and upwardly on the head 3' from the inlet (outlet)
2'. The head 3' is shown provided with a seal 6 and a lower
retaining plate 6' (bearing and seal) held on the upper end
of the valve stem 3 by hexagonal nuts and washers 8, 8'.
Upper and lower retaining plates and piston seals are shown
at 10, with 'O' rings about the flu~d supply and return pipes
7' and 7; and a further seal washer 12 at an upper flange of
the extrusion nozzle 15.
Should further control be desired of the nature, shape
and pattern and/or distribution of the fluid deposits (fila-
ments or fibers, droplets, etc. or combinations or the same
in various proportions) upon the moving web or other surface
that may be disposed below the valve-nozzle-aperture head
1-15 (schematically designated by W in Figs. 1 and 2), the
atomizer insert A may be coaxially circumscribed, totally or
in sectors, by an outer houslng sleeve H. The sleeve H is
provided with an air-flow or other fLuid flow passage H'
external to the member A, supplied at 22, and that terminates
in downwardly and centrally inwardly oriented exiting trim
ear portions H' to direct further pressurized air or other
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pressurized fluid) axially inwardly, on the fluid filament
shown at the region P in Fig. l, well below the nozzle and
insert openings N'-A'. The inwardly directed air cone provi-
ded through the V channel in A, acting symmetrically below
the nozzle openings N' and upon the free-flight extruded
fluid spray, may be modified, including directionally deflec-
ted, by the supplemental trim ear air at ~', and has been
found remarkably to bond continuous very thin filaments or
flbers (order of O.Olmm) and/or provide droplets or combina-
tions of the same in a controlled and predictable manner to
produce the desired coating distribution and dimensions upon
the web W, and in either continuous or programmable inter-
mittent fashion. Additional air supplied at 24 and from
other ears, labelled "FAN EARS" in Fig. 4, not shown in Fig.
1 but in back of and in front the nozzle section 15, disposed
90 circumferentially displaced from H', for example, can
further enable pattern deflection and containing.
For intermittent operation of the poppet or slmllar
valve 1, it has been found possible even to obtain substan-
tially the same fiber or filament uniform coating patterns
of, for example, hot melt elastomeric rubber, acrylic or
ethelyne vinyl acetate, etc., such as, for example, Findlay
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Company Type 990-3346, irrespective of intermittency fre-
quency (with fluLd volume extrusion synchronized with ~eb
speed and synchronized air flow volumes/velocity, where used)
over wide ranges of such speeds ranging from about 15 to hi~h
180 meters/minute line speeds, more or less. A hollow needle
stem applicator N about lO mm long and 0.35 mm ln diameter,
communicating with a carbide wear-resistant insert 13 of
about 0.75 mm insider diameter, is useful for this applica-
tion, with fiber-to-droplet ad~ustments ranging from about
0.457 mm above A (Fig. 3A) to about 0.457 mm beyond A (Fig.
3C). Air-shaping by air flow volume ranging from about 12 to
about 65 liters per minute, directed, for example, at P,
approximately 6 mm below th4 point of release of the fluid,
has been found to distribute continuous fibers of the order
of 0.01 mm thick over patterns ranging from about 6 mm to 38
mm in width, more or less--and with sharp cut-on and cut-off
edges, even at high line speeds, for intermittent operation.
The relatlvely remote position oE the fluid nozzle in
my prior U.S. Patent No. 4,565,217 enabled separation by an
intermediate fluicl discharge plate; but the additional capa-
citance effect caused by the remote nozzle positioning was
found in some instances to cause heavy droplets of coating
flu$d when the valve is closed. At high reciprocation rates,
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moreover, the "punching" action induces fluid column effects
that drive additional fluld through the nozzle during the
closlng action.
For avoiding such effects, the present invention on the
other hand, in effect imbeds the fluid nozzle structure 15
into the poppet valve fluid supply chamber 5' and enables
direct contact with the poppet valve stem 3, with the dimen-
sions of the hollow insert 13 and the preferably narrower
needle tube applicator N ad~usted such that the before-men-
tloned addltional capacitance of my prior system is entirely
obviated and no spurious fluid droplet deposits after valve
closure result. The design thus provides for less fluid dis-
placement during valve closure. In addition the valve stem
reciprocating stroke of the present invention has been
reduced (to the order of 0.020"--about one-third of that used
in prior commercial forms of my before-described patented
three-way poppet valve) which prevents any fluid column
effect emanating from longer stroke inducement of addltional
fluid displacement through the nozzle.
A preferred system for operatlng the poppet-valve-
nozzle sy~tem of Figs. l and 2 is shown in Fig. 4, wlth the
valve assembly 1 qhown supplied by hot melt supply line 7'
from the positive displacement metering pump MP, driven by a
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digital motor drive under the control of a speed control con-
nected with a web-speed pick-up sensor, in conventional
fashion, as so-labelled, for preferred synchronous meter
fluLd volume and web line speed. The air supplied at A' via
line ZO ("CONE") and at H' via line 22 (and, if used, from
the before-mentioned "FAN EARS") is heated at H in view of
the hot melt fluid useage, and its flow (volume/velocity) is
also preferably synchronously (proportionally) controlled
with fluid volume and web line speed at S.
While the three-way poppet valve herein-described with
direct supply line 7' and return 7 to the hot melt source or
tank is preferred, the novel nozzle-valve construction and
also the novel air interaction structures, if used, may also
be employed with two-way poppet valve constructions, though
this is not considered as operationally desirable as the
three-way valve. Thus, a two-way poppet valve construction
is shown in Fig. 5, otherwise slmilar to the three-way poppet
valve of Figs. 1 and 2, but with a closed upper fluid chamber
5" that is not returned by a return outlet 7 as in the system
of Fig. 4. Instead, the two-way valve system is provided in
the supply line 7', Fig. 6, with a pressure relief valve PR
designed to operate open for fluid passage when the two-way
poppet valve is closed for intermittent ON/OFF operation, and
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is connected back to the delivery reservoir or supply tank.
During closure of the two-way poppet valve, the PR vaLve will
redirect the supply fluid to the reservoir tank. Under cer-
tain conditions, the combination of such a two-way poppet
valve, together with PR valve, will provide for reasonable
satisfactory operation, effective up to the point when the PR
valve becomes operational, and therefore partially or totally
directing all fluid through the PR valve and no fluid to the
head 1, by-passing the head and supply chamber 5'.
For excellent uniform hot melt thin fiber-filament
coatings, moreover, it has been found important to locate the
poppet-valve fluid metering pump right at, or adjacent the
poppet valve 1. The mounting of the metering pump to the
valve assembly is therefore shown in Figs. 7A and 7B for the
three-way and two-way poppet valve assemblies of Figs. 1 and
5 (Figs. 4 and 6), respectively.
Further modifications will occur to those skilled in
this art, including the use of other types oE vaLving (though
generally properly generically describable of "poppet"-type),
and other types of fine spray nozzles or orifices, and such
are considered to fall withln the spirit and scope of the
invention as defined in the appended claims.
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